January 9, 2013
NASA Scientists Discover New Asteroid Belt Orbiting Vega
redOrbit Staff & Wire Reports - Your Universe Online
A team of U.S. astronomers has discovered what looks to be a large asteroid belt orbiting around Vega, the second-brightest star in the northern sky, NASA officials announced on Tuesday.
Using data obtained from the Spitzer Space Telescope and the European Space Agency's (ESA) Herschel Space Observatory, the researchers discovered infrared light emitted by warm and cold dust in bands around both Vega and Fomalhaut, a second star already known to be home to a debris belt.
“The Herschel and Spitzer telescopes detected infrared light emitted by warm and cold dust in discrete bands around Vega and Fomalhaut, discovering the new asteroid belt around Vega and confirming the existence of the other belts around both stars,” the researchers said in a statement.
“The data are consistent with both stars having inner, warm belts and outer, cool belts separated by a gap. This architecture is similar to the asteroid and Kuiper belts in our own solar system,” they added.
The findings were presented Tuesday at the American Astronomical Society (AAS) meeting in Long Beach, California, and will also be detailed in a paper set for publication in the Astrophysical Journal. The lead author of that paper, University of Arizona astronomer Kate Su, said that her team´s research helps to confirm that multiple-planet systems are relatively common outside of our own solar system.
Despite the similarities, there are also some key differences between the Vega and Formalhaut belts and those closest to Earth, said NASA scientists. Both stars´ inner and outer belts contain far more material that our asteroid and Kuiper belts, partially because the systems are much younger than ours and partially because they were probably formed by a cloud of gas and dust that was initially more massive that our solar system´s.
“The gap between the inner and outer debris belts for Vega and Fomalhaut also proportionally corresponds to the distance between our sun's asteroid and Kuiper belts,” the space agency said. “This distance works out to a ratio of about 1:10, with the outer belt 10 times farther from its host star than the inner belt.”
“As for the large gap between the two belts, it is likely there are several undetected planets, Jupiter-size or smaller, creating a dust-free zone between the two belts. A good comparison star system is HR 8799, which has four known planets that sweep up the space between two similar disks of debris,” they added.
The large gap between warm and cold belts suggests that more than one planet is likely to be orbiting around both Vega and Fomalhaut, says Su. If those planets do exist, NASA researchers say that it is doubtful that they will remain out of sight for much longer thanks to the forthcoming James Webb Space Telescope (JWST) and other next-generation astronomical instruments.